Electroconductive layers

ABSTRACT

SHEET MATERIAL COATED ON AT LEAST ONE SIDE WITH AN ELECTROCONDUCTIVE LAYER FORMED ESSENTIALLY OF AN INITIALLY WATER-SOLUBLE ADDITION POLYMER OF PLURAL A,B-ETHYLENICALLY UNSATURATED MONOMERS, WHICH IS CONVERTIBLE BY HEATING TO WATER-SOLUBLE FORM BY AN INTERNAL CROSS-LINKING REACTION. 20-95 MOL PERCENT OF THE UNITS OF THE COPOLYMERS ARE DERIVED FROM AT LEAST ONE CATIONIC OR ANIONIC MONOMER CARRYING ELECTROCONDUCTIVE GROUPS, 5-80 MOL PERCENT OF SUCH UNITS ARE DERIVED FROM A MONOMER CARRYING REACTIVE HALOGEN ATOMS AND 0-44 MOL PERCENT OF SUCH UNITS ARE DERIVED FROM A MONOMER CARRYING AN ACIDIC GROUP IN FREE ACID OR SALT WHICH IS REACTIVE WITH THE HALOGEN ATOMS OF UNITS OF THE SECOND MENTIONED MONOMER, AT LEAST ABOUT 5 MOL PERCENT OF THE LAST MENTIONED MONOMERIC UNITS BEING PRESENT WHERE THE FIRST MENTIONED MONOMERIC UNITS ARE UNREACTIVE WITH THE HALOGEN ATOMS OF THE SECOND MEMTIONED MONOMERIC UNITS.

United States Patent US. Cl. 96-67 8 Claims ea. a .7

ABSTRAlIT OF THE DISCLGSURE Sheet material coated on at least one side with an electroconductive layer formed essentially of an initially water-soluble addition polymer of plural a,B-ethylenically unsaturated monomers which is convertible by heating to water-insoluble form by an internal cross-linking reaction. 2095 mol percent of the units of the copolymer are derived from at least one cationic or anionic monomer carrying electroconductive groups, 80 mol percent of such units are derived from a monomer carrying reactive halogen atoms and 0-44 mo] percent of such units are derived from a monomer carrying an acidic group in free acid or salt form which is reactive with the halogen atoms of units of the second mentioned monomer, at least about 5 mol percent of the last mentioned monomeric units being present where the first mentioned monomeric units are unreactive with the halogen atoms of the second mentioned monomeric units.

The invention relates to electroconductive layers for use in recording materials.

Electroconductive products are used in all kinds of recording materials to dissipate electrostatic charges. For instance, it is known that in normal photographic silver halide emulsion materials the usual synthetic film supports have the property of being charged electrostatically, so that the charged films strongly attract the surrounding dust and thereby become soiled at their surface. Moreover, when such films supports are provided with a silver halide emulsion layer discharge images may become visible in the light-sensitive layer upon development. Such an elecstostatic charging is caused by quickly moving the film support or light-sensitive photographic material during rolling or unrolling in the coating, cutting, or packing machines and by making the film run through the camera and the projector. It is also known that the static charging can be decreased by coating the synthetic resin support with a conductive auxiliary layer.

In other recording materials such as for use in electrostatic printing, an electrostatic charge is imparted to paper or to other dielectric supports in a determined pattern. The support is conductive or must be coated with a conductive layer. For instance, in an electrophotographic recording element a photoconductive layer stands in contact with an electroconductive layer or sheet, which serves for dissipating the electrostatic charges at the areas of the photoconductive layer undergoing an exposure to light rays.

In electrographic materials comprising an insulating layer whereon an electrostatic charge pattern is built up by image-wise or record-Wise charging, e.g. by means of a modulated electron beam, the conductive element (support or layer) serves to apply a voltage thereon, thus allowing the formation of the electrostatic charge pattern applied to the insulating top layer.

Electroconductive layers for carrying off electrostatic charges may also be useful in recording elements wherein photosensitive semiconductor compounds are reversely ac- 3,708,289 Patented Jan. 2, 1973 tivated by electromagnetic radiation and wherein the activated patterns provide irreversible images by an oxidation-reduction chemical process.

In the following description and claims the general term recording material is intended to include the type of materials used in all of the above described recording methods. In all these recording materials the surface resistivity of the electroconductive layer must not be higher than 10 ohm per sq. cm. at 15% of relative humidity.

It would be very desirable to utilize in such recording materials water-insoluble layers that are electroconductive. For instance, in photographic silver halide materials the electroconductive layer would not dissolve in one of the processing baths, but would remain present in the finished photographic material to prevent static charging and, e.g., prevent the attraction of dust on finished photographic images. In the electrographic and electrophotographic processes this is also of great importance, for in such processes, the insulating layer or the photoconductive layer could be coated from an aqueous solution. These effects would result in great economies.

There has been found a class of electroconductive copolymers, which can be rendered insoluble in water and can be used in anti-static layers in the above described light-sensitive photographic recording materials, in an electroconductive layer in an electrographic or electrophotographic recording element.

According to one aspect of the invention a sheet or webforming material of paper or synthetic polymers is provided, at least one side of which is coated with an electroconductive layer preferably having a surface resistivity lower than 10 ohm/sq. cm., said layer being composed mainly of a copolymer comprising:

(A) to 95 mole percent of randomly distributed units deriving from cationic or anionic monomers conferring electro-conductivity to the copolymer,

(B) 5 to 80 mole percent of randomly distributed units deriving from monomers carrying reactive halogen atoms,

(C) O to 44 mole percent, preferably 5 to 10 mole percent, of randomly distributed units deriving from monomers carrying groups that are reactive with the halogen atoms of units (B),

said copolymer being initially water-soluble and capable upon heating to 180 C. of becoming a cross-linked, water-insoluble copolymer.

Suitable units deriving from cationic monomers, which are responsible for the electro-conductivity of the copolymer, are units comprising quaternary ammonium salt groups, salt groups derived from primary, secondary or tertiary amines or tertiary sulphonium salt groups.

Examples of units comprising quaternary ammonium salt groups of tertiary sulphonium salt groups are for instance the units derived from:

fi-acryloylor B-methacryloyloxyethyl-trimethylammonium chloride,

B-acryloylor B-methacryloyloxyethyl-trimethylammonium methylsulphate,

N-acryloylor N-methacryloyloxyethyl-pyridinium chloride,

2-hydroxy-3-acryloylor -methacryloyloxypropyl-trimethylammonium chloride,

3-acrylamidoor 3-methacrylamidopropyl trimethylammonium chloride,

fl-acryloylor fl-methacryloyloxyethyl dimethylsulphonium chloride,

vinylbenzyl-trimethylammonium chloride,

1,Z-dimethyl-S-vinylpyridinium methylsulphate,

N-methyl-4-vinylpyridinium chloride,

N-methyl-4-vinylpyridinium methylsulphate,

N-methyl-2-vinylpyridinium methylsulphate, N-methyl-4-vinylpyridinium iodide, 2,3-dimethyl-N-vinylimidazolinium chloride.

Examples of units comprising salt groups derived from amines are:

acryloylor methacryloyloxyethyl-diethylammonium chloride,

acryloylor methacryloyloxyethyl-dimethylammonium chloride,

4-vinylpyridinium chloride,

2-vinylpyridinium chloride,

2-methyl-S-vinylpyridinium chloride.

As units deriving from anionic monomers that are responsible for the electro-conductivity of the whole copolymer can be used units comprising carboxyl groups in their alkali metal or ammonium salt form and sulphonic acid or phosphonic acid groups. The latter two groups may occur in their free acid form as well as in their alkali metal or ammonium salt form. Examples of monomers comprising the above acid groups are acrylic acid, methacrylic acid maleic acid, itaconic acid, citraconic acid, vinylbenzoic acid, vinylsulphonic acid, styrene-sulphonic acid, 'y-sulphopropylacrylate, fi-sulphobutyl acrylate, and vinylphosphonic acid.

The second class of randomly distributed units constituting the copolymer molecules is formed by units deriving from monomers carrying reactive halogen atoms, particularly chlorine and bromine atoms. Suitable monomers are those wherein a halogen atom is attached to a carbon,

which is in u-position with respect to an activating group such as -C0.0, O.OC--, CO.O.CH

-CH(OH) and aromatic radicals. Specific examples of suitable monomers for use according to the invention are:

por m-vinylbenzyl chloride or their mixtures, a-chloroacrylic acid,

chloromethylacrylate or methacrylate, u-chloroethylacrylate or methacrylate, fl-chloroethylacrylate or methacrylate, fl-bromoethylacrylate or methacrylate, 'y-chloro-fl-hydroxypropyl acrylate or methacrylate, vinyl bromoacetate,

vinyl chloroacetate.

The copolymers may also comprise units of the third class, which carry groups that are reactive with the halogen atoms of the preceding class of monomers. Especially interesting are alkali metal or ammonium salts of carboxylic acid groups, further sulphonic acid or phosphonic acid groups as Well as their alkali metal or ammonium salts. Specific examples of suitable monomers of the third class for use according to the invention are the alkali metal or ammonium salts of maleic acid, acrylic acid, methacrylic acid, vinylbenzoic acid, itaconic acid, crotonic acid, and citraconic acid.

The reactivity of the halogen atom in some units of the second class is very high, e.g. in vinylbenzyl chloride. When the copolymer comprises these reactive halogencontaining units it is no longer necessary to include units of the third class in the copolymer, since the sole presence of electroconductive units and of units containing halogen atoms with a very high reactivity suflices to yield cross-linked and thus insolubilized copolymers upon heating. Further, when the electroconductive units comprise anionic groups, which easily react with halogen atoms, the third group of units in the copolymer can also be omitted. In all these cases the final copolymer only comprises units of the first and of the second class.

Some of the electroconductive copolymers may comprise, in addition to the reactive halogen-containing units, electro-conductive units deriving from anionic and from cationic monomers. This is the case when for instance the 4 copolymers comprise units containing quaternary ammonium salt groups together with units containing carboxyl groups in their alkali metal or ammonium salt form.

The electroconductive copolymers of the invention can be prepared by known copolymerisation techniques, starting from mixtures of different a,fi-ethylenically unsaturated monomers respectively comprising the groups needed in the final copolymers. Yet, it is not necessary to copolymerise three different monomers (in some cases two monomers as indicated above), which already comprise the desired groups. These groups can also be introduced in existing polymers or copolymers by kown reactions. For instance, the units comprising quaternary ammonium salt groups can be formed by quaternization of chloromethyl-styrene units, or of acryloyl or methacryloyl oxyalkyl chloride units. Further, styrene units can be sulphonated to styrene sulphonic acid units, or acrylic acid units can be made to react with 1,3-propane sultone or 1,4-butane sultone, or acrylic acid units can be formed by partial saponification of B-chloroethyl acrylate.

The copolymers of the invention are water-soluble as a result of the large number of anionic or cationic units, that are distributed randomly over the polymer chain. However, owing to the presence of units containing reactive halogen atoms and to units comprising groups that are reactive with these halogen atoms, cross-linking between adjacent molecule chains occurs upon heating, whereby the copolymer finally becomes insoluble. A layer of the copolymer applied to any support from aqueous or organic solution, becomes completely resistant to water upon heating and accordingly remains undisturbed, e.g. when in an electrographic recording element the photoconductive layer is deposited on the electroconductive copolymer layer from an aqueous solution or dispersion. If the layer would not become insoluble in water, it would be partly dissolved and mixed with the photoconductive material, so that it would not be possible any longer to retain an electric charge in the photoconductive material.

The insolubility in water after drying of the copolymer layer is also of great importance in the case of photographic silver halide recording materials. Indeed, the electroconductive layer cannot be dissolved away in the processing baths and its antistatic properties are preserved in the finished photographic film material. The surrounding dust does not deposit any longer on such processed film material.

After having applied a solution of the copolymer onto a support and having eliminated the solvent or solvents by known means, the coating is heated to 30-180 C. depending on the particular copolymer used so that crosslinking occurs between the copolymer molecules. As a result of this cross-linking reaction the copolymer layer becomes insoluble in water. Cross-linking is effected below the temperature, at which charring or damage to the support may take place. In general, the curing time may vary between 1 and 5 minutes. The material is passed through a curing oven heated to the curing temperature.

The electroconductivity of the copolymers is proportional to the mole percent of cationic or anionic monomeric units conferring electroconductivity to the copolymers. It has been found that at least 20 mole percent, preferably at least 50 mole percent of these units must be present to allow the copolymers to be used as electroconductive polymeric material in any image-recording element.

The electroconductivity of the copolymers is determined by measurement of their surface resistivity. A 10% by weight solution of the copolymer is applied therefor to a glass plate. The resulting layer is dried and conditioned at a specific relative humidity. The resistivity measurements are performed by means of a cell, both poles of which have a width of 0.5 cm. and are placed at a distance of 1 cm. from each other. In order to have a sufficient conductivity and to allow the use of the copolymers of the invention in an electroconductive layer in an imagerecording element, the surface resistivity should not exceed certain limits, which themselves are influenced by the relative humidity degree. For instance, the surface resistivity at 15% of relative humidity must not be higher than 10 oh'm/ sq. cm., whereas at 70% of relative humidity the surface resistivity must certainly not be higher than 10 ohm/sq. cm.

From 5 to 80 mole percent of units comprising reactive halogen atoms may be present in the copolymer and from to 44 mole percent may be formed by units comprising groups that are reactive with halogen atoms. When the copolymer comprises but two kinds of monomeric units as set forth above, for instance anionic monomeric units and units comprising reactive halogen atoms, the number of the electroconductive units may be much higher. It was very remarkable that the presence of only to of units containing halogen atoms already resulted in a sufiicient cross-linking upon heating of the copolymer molecules and insolubilisation of the copolymer layer. In this case the number of electroconductive units may amount to 95 mole percent, so that the electroconductivity of the copolymer increases accordingly.

Before heating, the copolymers of the invention are soluble in water, in organic solvents, or in mixtures of organic solvents and water, especially when the mole percent of electroconductive monomeric units is very high, thus making it possible to apply them as a coating composition to a support by spray, brush, roller, doctor blade, air brush, or wiping techniques. Examples of supports are paper, films of synthetic polymers such as films of cellulose acetate, polystyrene, polyesters or polycarbonates. If needed, the different supports may be provided previously with known subbing layers, whereon the electroconductive layer is coated afterwards.

The electroconductive copolymers also impart electroconductivity, when a paper base used as support, is thoroughly soaked with a solution of the electroconductive polymeric material according to the invention. So, the electroconductive copolymers remain dispersed throughout the entire dry paper base. Electroconductivity may also be conferred to the paper base by adding a sufiicient quantity of copolymer solution to the papermaking pulp.

In an electroconductive layer according to the invention an amount of dry copolymer varying between 0.5 and 5 g./sq. m. of support will in general be suflicient. When using paper as the support, care is to be taken also that about 4% by weight of copolymer be present with respect to the weight of dry solids of the paper support.

The invention is not restricted to the use in electroconductive layers of copolymers only comprising the units as defined above. Indeed, when using styrene-sulphonic acid for the electroconductive units, there will practically always be present a certain number of styrene units. Further, whenever necessary, a small amount of other units may be present in the copolymer, e.g. plasticizing units such as alkyl acrylate units. In this case too a material is obtained, which is useful as electroconductive layer that is soluble in water, in organic solvents, or in mixtures of organic solvents and water, and which can be cross-linked and thus rendered insoluble by a simple heat treatment.

The composition of the electroconductive layer may also include stabilizing agents, plasticizers, dispersing agents, pigments, hydrophilic binders, e.g. gelatin, and hydrophobic binders, e.g. cellulose diacetate or cellulose triacetate. Due care must be taken to avoid precipitation of the copolymer and of said binder.

When the electroconductive layer of the invention is to be used as an antistatic layer in a photographic silver halide recording material, the electroconductive layer is generally applied to the rear of the photographic film. It can, however, also be applied as an interlayer between the support and the light-sensitive emulsion layer or layers.

It the electroconductive layer is to be used in an electrophotograyhic recording material, a photoconductive coating is applied on top thereof. This coating is prepared by dispersing or dissolving the photoconductive substance or substances in an aqueous or organic solution of an insulating binder or in a solution of such insulating binder in a mixture of an organic solvent and water, and by applying the dispersion or solution in the form of a layer to the electroconductive surface. Even if the photoconductive layer is applied from aqueous solution or dispersion, there is no danger that the electroconductive polymeric material would wholly or partly dissolve. Indeed, since the copolymers of the invention become insoluble in water upon heating, at the most a relatively low swelling of the electroconductive layer would occur, thus leaving upon drying of the aqueous dispersion or solution of photoconductive material a recording layer having a quick and high chargeability and a high sensitivity.

The electrophotographic recording element prepared with the electroconductive copolymer of the present invention is flexible and possesses very good mechanical strength. A very good adhesion exists between the paper support and the electroconductive layer.

The present invention puts an end to the ditficulties in electrophotography, which hitherto have been described in the literature with respect to the precise composition of a separation layer between a paper soaked with salts or a paper web covered with the formerly known electroconductive copolymers and a photoconductive material applied from aqueous phase. Indeed, when using the electroconductive copolymers according to the invention in such a separation layer all the favourable characteristics of the present invention are utilized. Electrophotographic images are obtained, which only in respect of quality are dependent on the composition of the photoconductive layer and which are not disturbed anymore by unfavourable properties of formerly used electronconductive substances.

The preparation of electroconductive copolymers according to this invention is described in the following preparations.

PREPARATIONS (1) Copolymer of N-acryloyloxyethylpyridinium chloride, p-chloroethyl acrylate, and sodium acrylate (A) Poly-B-chloroethyl acrylate.In a reaction vessel equipped with a stirrer, a reflux condenser and a nitrogen inlet 134.5 g. of fi-chloroethyl acrylate are dissolved in benzene and filled up with benzene to 500 ml. To this solution 134.5 mg. of azo-bis-isobutyronitrile are added. The solution is then heated to C. while stirring and bubbling nitrogen through it.

During the first 15 minutes the polymerization is slightly exothermic. The heating is stopped since the reaction medium remains at reflux temperature as a result of the exothermic polymerization reaction. After the exothermic reaction the reaction mixture is heated for another 16 hours at reflux temperature.

Poly-fl-chloroethyl acrylate is isolated from the solution by pouring the benzene solution in 3 l. of methanol. A sticky polymer residue is formed, which after rinsing with 1 l. of methanol is dissolved in acetone.

Yield: 125.8 g. of poly-fi-chloroethyl acrylate having an intrinsic viscosity of 0.48 dl./g. in acetone at 25 C.

(B) Quaternization.386 g. of the acetone solution prepared as described under (A) and comprising 121 g. of poly-[i-chloroethyl acrylate are brought in a reaction vessel equipped with a stirrer, a thermometer and a distillation apparatus with a Liebig condenser. To the resulting solution 213.5 g. of pyridine are added. While stirring acetone is distilled off, until the temperature of the pyridine solution reaches C.

Subsequently the distillation apparatus is replaced by a reflux condenser and the reaction mass is heated further on an oil-bath at 100 C. while stirring. After 4 hours of reaction a partially quaternized polymer deposits. Then 50 ml. of ethanol are added so that the solution becomes homogeneously clear again. Two hours later the solution is again turbid and another 50 ml. of ethanol are added.

After 14 hours of reaction on an oil-bath at 100 C. a viscous opal solution is obtained, in which upon addition of 1 l. of dioxan a sticky polymer deposits. The resulting polymer is purified by dissolving in 500 ml. of methanol and precipitating in l. of dioxan. After filtration the polymer is dissolved in water whereupon the pH of the resulting solution is raised from 4.8 to 7.0 by means of sodium hydroxide. A clear neutral solution is obtained, from which upon evaporation of approximately 300 ml. in vacuo the remaining pyridine is removed.

Yield: 1 l. of solution comprising 140 g. of copolymer. The copolymer formed has an intrinsic viscosity of 0.314 dl./g. in a N/ solution of sodium chloride at 25 C.

The copolymer is composed of the following recurring units, which are randomly distributed over the polymer chains:

The proportion of these recurring units is 38.2, 58.4, and 3.4 mole percent respectively.

(2) A solution of 26.9 g. of poly-B-chloroethyl acrylate in 23.5 g. of acetone is brought in a reaction vessel (see preparation 1(A)), and 50 g. of pyridine are added thereto. The solution is then heated on an oil-bath, whereupon the acetone is distilled till the temperature in the reaction vessel reaches 80 C. Then 5 ml. of water are added and the distillation is continued till the temperature reaches 90 C. Subsequently, there is quaternized for 5 hours at 90 C., whereupon ml. of water are added. A viscous bright solution is obtained, which is purified in the same way as described in preparation 1(B).

Yield: 32.32 g. of copolymer having the same structure as the copolymer in 1(B), but wherein the proportion of the recurring units is now 20, 76 and 4 mole percent respectively.

(3) Copolymer of N-acryloyloxymethylpyridinium chloride, 5 chloroethyl acrylate, and acrylic acid (pyridinium salt) (A) Emulsion copolymerization of ,8 chloroethyl acrylate and acrylic acid.--In a reaction vessel equipped with a stirrer, a nitrogen inlet, a thermometer, and a reflux condenser 3.55 g. of a 90% aqueous solution of dodecylated oxydibenzene disodium sulphonate and 11.4 g. of a 28% aqueous solution of the sodium salt of tetradecyl sulphate are added to 300 ml. of water. Then 121.1 g. of fl-chloroethyl acrylate, 7.2 g. of acrylic acid, and 1.28 g. of potassium persulphate are added thereto at room temperature. While stirring and conducting a gentle nitrogen current through the emulsion, the latter is heated gradually to 70 C. The polymerization is exothermic and the temperature is maintained at 70 C. by cooling.

After the exothermic phase the emulsion is stirred for another 90 minutes at 70 C. The copolymer is isolated from the latex by the addition of methanol. The precipitated copolymer of fi-chloroethyl acrylate and acrylic acid is purified by dissolving in acetone and pouring in water.

Yield: 112.8 g. of copolymer containing 93 mole percent of j8-chloroethyl acrylate and 7 mole percent of acrylic acid.

(B) Quaternization.570 ml. of a solution of 64.15 g. of the copolymer formed as described under (A) in methylene chloride are brought in a reaction vessel fitted with a stirrer,- a thermometer, a rectifying column and a distillation apparatus with a Liebig condenser. Then 525 g. of pyridine are added to the resulting solution and 320 ml. are distilled. The reflux temperature of the reaction medium has then risen to 75 C. Subsequently 50 ml. of ethanol are added and the mixture is heated at reflux temperature for 15 hours. Then 250 ml. of ethanol are added, while the reaction medium is maintained at reflux temperature. After a reaction time of 40 hours the quaternized polymer is not yet soluble in water. Thereupon 250 ml. of liquid are distilled and the reflux temperature rises to 82 C. The reaction is allowed to continue at this temperature for 5 more hours. A watersoluble product is obtained. By the addition of 1 l. of acetone the copolymer is precipitated. It is washed three times with acetone and then dissolved in water. After filtration approximately 3 l. of solution are obtained, which are concentrated by evaporation in vacuo to 1.5 1.

Yield: 73.5 g. of copolymer comprising the following recurring units:

I Cl- Proportion of the recurring units: 25.5, 38.5, and 36 mole percent respectively.

(4)(A) The process of preparation 3(A) is repeated, but is started with the following reagents:

128.1 g. of fi-chloroethyl acrylate,

3.6 g. of acrylic acid,

6.5 g. of the sodium salt of oleylmethyltauride,

1.31 g. of potassium persulphate,

117 g. of a copolymer comprising 3.6 mole percent of acrylic acid and 96.4 mole percent of fi-chloroethyl acrylate are obtained.

(B) When the copolymer formed is quaternized as described under 4(A) with pyridine according to the process of 3(B), a copolymer comprising 23.2, 33.0, and 43.8 mole percent of recurring units is obtained.

(5) Copolymer of 1,2-dimethyl-5-vinylpyridinium methylsulphate, sodium acrylate, and fi-chloroethyl acrylate In a reaction vessel of 250 ml. equipped with a stirrer, a thermometer, and a nitrogen inlet, are placed g. of 1,2-dimethyl-S-vinylpyridinium methylsulphate (prepared as described in the Belgian patent specification 730,311) and 10 g. of acrylic acid. Water is added till ml. of solution is obtained. Then 1 g. of potassium persulphate and 60 m1. of a dimethylformamide solution wherein 10 g. of fi-chloroethyl acrylate are dissolved are added thereto.

The resulting solution is heated to 70 C. and maintained at this temperature for 3 /2 hours, while a nitrogen current is led through it.

An opal viscous solution is obtained, from which the copolymer formed is isolated by pouring in acetone. A

l CH CHaSOi' 'L COONaJ The proportion of these units is 60.6, 25.7, and 13.7 mole percent respectively.

(6) The process of preparation is repeated, but is started from the following amounts of monomers:

60 g. of 1,2-dimethyl-5-vinylpyridinium methylsulphate 10 g. of acrylic acid 30 g. of fi-chloroethyl acrylate.

Yield: 600 ml. of solution comprising 87 g. of copolymer as in preparation 4. The proportion of the randomly distributed units is now 46, 25, and 29 mole percent respectively.

(7) Copolymer of vinylbenzyltrimethylammonium chloride, vinyl benzyl chloride, and sodium acrylate (A) Copolymer of vinyltoluene and acrylic acid.In a reaction vessel of 500 ml. equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet, 3.21 g. of a 90% aqueous solution of dodecylated oxydibenzene disodium sulphonate, 10.3 g. of 28% aqueous solution of the sodium salt of tetradecyl sulphate, and 1.16 g. of ammonium persulphate are dissolved in 250 ml. of demineralized water. With stirring a mixture of 112 g. (0.95 mole) of vinyltoluene and 3.6 g. (0.05 mole) of acrylic acid is added whilst nitrogen is bubbled through the reaction mass. The emulsion is heated to 70 C. and maintained at this temperature for 4 hours. Initially the polymerization is exothermic so that the reaction meduim must be cooled. A homogeneous latex is formed, from which the copolymer of vinyltoluene and acrylic acid is isolated by addition of acetone. This precipitate is washed in l l. of methanol and then dried in vacuo at 45 C.

Yield: 112 g. of copolymer of vinyltoluene and acrylic acid, which comprises 4.5 mole percent of acrylic acid groups and 95.5 mole percent of vinyltoluene groups.

The copolymer has an intrinsic viscosity of 1.26 dl./g. in butanone at C.

(B) Copolymer of chloromethylstyrene and acrylic acid.In a reaction vessel equipped with a reflux condenser, a stirrer, and a dropping funnel, 60.8 g. of the copolymer of vinyltoluene and acrylic acid prepared as described above are dissolved in 600 ml. of carbon tetrachloride. Then 100 ml. of liquid are distilled from this solution, whereupon 500 mg. of benzoyl peroxide are added. Subsequently 135 g. of sulphuryl chloride are added dropwise at 70 C. As the chlorination is exothermic this dropwise addition is regulated in such a way that the whole amount of sulphuryl chloride is added within 45 minutes. Sulphur dioxide and hydrochloric acid evolve through the reflux condenser.

The reaction medium is then maintained at 70 C. for 3 /2 more hours while stirring, diluted with 300 m1. of

10 carbon tetrachloride and poured in 4 litres of methanol. After washing twice with 0.5 l. of methanol the copolymer of chloromethylstyrene and acrylic acid is dissolved in methylene chloride.

Yield: 84 g. of copolymer having an intrinsic viscosity of 0.62 dL/g. in methylene chloride at 25 C., and comprising 95.5 mole percent of chloromethylstyrene groups and 4.5 mole percent acrylic acid groups.

(C) Quaternization.--In a reaction vessel equipped with a stirrer, a reflux condenser, and a dropping funnel, 13.4 g. of the copolymer prepared as described under (B) are added to 70 ml. of dimethylformamide and 35 ml. of methanol. To the resulting solution a mixture of the fol lowing ingredients is added gradually at 25 C.:

5 ml. of a 40% aqueous solution of trimethylamine 7 ml. of methanol 3 ml. of dimethylformamide The quaternization is Weakly exothermic and after 15 minutes of reaction the temperature in the solution has risen to 30 C. Subsequently the solution is heated to 40 C. and this temperature is maintained for 1 more hour whilst stirring. The solution is then poured in 1 l. of acetone and after washing and filtering, dissolved again in water. The pH of the solution is brought from 2.0 to 6.3 by the addition of a few drops of sodium hydroxide solution.

Yield: 200 ml. of a solution comprising 12.4 g. of copolymer composed of randomly distributed units according to the following formulae:

L local The proportion of the randomly distributed units is 30.5, 65, and 4.5 mole percent respectively.

(8) The process of preparation 7(C) is repeated, but is started from 13.4 g. of copolymer of chloromethylstyrene and acrylic acid (see preparation 7(B)) and 14.8 ml. of 40% aqueous solution of trimethylamine.

Yield: 385 ml. of solution comprising 13.85 g. of a copolymer of vinylbenzyltrimethylammoniurn chloride, vinylbenzyl chloride, and sodium acrylate, comprising the above indicated randomly distributed units in a proportion of 50, 45 and 5 mole percent respectively.

(9)(A) The process of preparation 7(A) is repeated, but is started from 106 g. of vinyltoluene and 7.2 g. of acrylic acid. A copolymer of vinyltoluene and acrylic acid is formed, which comprises 8.8 mole percent of acrylic acid, and has an intrinsic viscosity of 0.87 dL/g. in butanone at 25 C.

11 (B) By starting from this copolymer the process of preparation 7 (B) is repeated with the proviso, however, that the amount of the products is changed as follows:

63 g. of copolymer of vinyltoluene and acrylic acid, as

prepared above,

135 g. of sulphuryl chloride 500 mg. of benzoyl peroxide Yield: 85.5 g. of copolymer of chloromethylstyrene ano acrylic acid, which comprises 91.2 mole percent of chloromethylstyrene, and has an intrinsic viscosity of 0.50 dl./ g. in methylene chloride at 25 C.

(C) The process of preparation (C) is repeated, but is started from the following reaction mixture:

12.55 g. of the copolymer prepared as described in 9(B) 7.4 ml. of a 40% aqueous solution of trimethylamine.

Yield: 250 ml. of solution comprising 12.4 g. of copolymer, which contains the recurring units indicated in preparation 7 (C), but in a proportion of 30, 61.2, and 8.8 mole percent respectively.

(10) The process of 9(C) is repeated, but is started from the following products 12.55 g. of copolymer formed as described in 9(B) 14.8 ml. of 40% aqueous solution of trimethylamine Yield: 305 ml. of a solution comprising 17.7 g. of dissolved copolymer with the same composition as in 9(C) but wherein the proportion of the recurring units is 51, 40 and 9 mole percent respectively.

(11) Copolymer of vinylbenzyltrimethylammonium chloride, vinylbenzyl chloride, and sodium acrylate (A) Copolymer of vinyltoluene and acrylic acid.The process of preparation 7(A) is repeated, but is started from the following reagents:

1.12 kg. of vinyltoluene 36 g. of acrylic acid 32.1 g. of 90% aqueous solution of dodecylated oxydibenzene disodium sulphonate 103 g. of 28% aqueous solution of the sodium salt of tetradecyl sulphate 11.6 g. of ammonium persulphate 2 l. of water.

Yield: 1137 g. of copolymer comprising 91.8 mole percent of vinyltoluene and 8.2 mole percent of acrylic acid.

(B) Copolymer of chloromethylstyrene and acrylic acid.The porcess of preparation 7(B) is repeated, but is started from the following reagents:

462.4 g. of the copolymer prepared as described under (A) and dried at 50 C. for 8 hours 6.4 l. of carbon tetrachloride.

Then 400 ml. of liquid are distilled and 3.8 g. of benzoyl peroxide are added. Subsequently 1025 g. of sulphuryl chloride are added dropwise. Heating is then continued for 3 hours at 70 C.

Yield: 556 g. of copolymer comprising 8 mole percent of acrylic acid and 92 mole percent of vinylbenzyl chloride, having an intrinsic viscosity of 0.43 dl./ g. in methylene chloride at C.

(C) Quaternization.A solution of 100 g. of the copolymer prepared as described under (B) 672 g. of ethylene glycol monomethyl ether is brought in a reaction vessel equipped with a stirrer, a reflux condenser, and a dropping funnel. A solution of 59.2 ml. of 40% aqueous solution of trimethylamine and 100 ml. of ethylene glycol monomethyl ether are added dropwise in 45 minutes at 30 C. while the neutral solution is stirred.

The quaternization is slightly exothermic and the temperature rises to C. The mixture is then heated to C. and the quaternization is allowed to continue for 4 hours at the same temperature.

The solution is then poured in 5 l. of acetone. After filtration and washing with 1 l. of acetone a fibrous white precipitate is obtained, which is dissolved in water and brought at pH 7 by the addition of sodium hydroxide.

Yield: 96.3 g. of copolymer having an intrinsic viscosity of 0.216 dl./g. in a N/ 10 aqueous solution of sodium chloride at 2 5 C. The copolymer comprises the following randomly distributed recurring units in a proportion of 29.5, 65.3 and 5.2 mole percent respectively:

L 800ml 12) The process of preparation 11(C) is repeated with the following reagents:

g. of copolymer of 11(B) 672 g. of ethylene glycol monomethyl ether 88.6 ml. of 40% aqueous solution of trimethylamine.

Yield: 92.12 g. of copolymer as in 11(C) having an intrinsic viscosity of 0.40 dL/g. and a proportion of the recurring units of 46, 49.8, and 4.2 mole percent respectively.

(13) The process of preparation 11(C) is repeated with the following reagents:

100 g. of copolymer of 11(B) 672 g. of ethylene glycol monomethyl ether 118.5 ml. of a 40% aqueous solution of trimethylamine.

Yield: 128.3 g. of a copolymer as in 11(C) having an intrinsic viscosity of 0.25 dl./ g. and a proportion of recurring units of 51.8, 43.9, and 4.3 mole percent respectively.

(14) Copolymer of N-acryloyloxyethyltrimethylammonium chloride, sodium acrylate, and fl-chloroethyl acrylate 12.82 g. of a copolymer of acrylic acid and fi-chloroethyl acrylate comprising 13.6 mole percent of acrylic acid and 86.4 mole percent of B-chloroethyl acrylate and 70 ml. of dirnethylformamide are placed in a pressure tube. To the resulting solution 14.78 ml. of 40% aqueous solution of trimethylamine and 20 ml. of water are added. The pressure tube is sealed and then heated for 16 hours at 60 C. The quaternized polymer has precipitated partially in the form of a gel after these 16 hours.

The soluble fraction is filtered off and poured in a mixture of 500 ml. of benzene and 500 ml. of acetone. The residue is dissolved in water and the pH of the solution is brought to 7 by the addition of sodium hydroxide. The solution is then concentrated by evaporation to 60 ml.

Yield: 8 g. of copolymer composed of randomly distributed units corresponding to the following structural formulae:

CHz-CH and OHz-CH- L COONaJ Proportion of the recurring units: 26.8, 59.4, and 13.8 mole percent respectively.

(15) 15 g. of copolymer composed of 88 mole percent of acrylic acid and 12 mole percent of B-chloroethyl acrylate are dissolved in 150 ml. of water and brought to pH 7 with sodium hydroxide. The resulting solution is diluted with water to 200 m1. Then 1.65 ml. of 40% aqueous solution of trimethylamine is added, and the temperature is raised at 40 C. and maintained for 2 hours.

The reaction mixture is concentrated by evaporation in vacuo to 100 ml. and then poured in 1 1. of methanol. After filtration and washing with 300 ml. of methanol, the copolymer is dissolved in water.

Yield: 18.4 g. of copolymer with the same recurring units as in preparation 14, but in a proportion of 1, l1, and 88 mole percent respectively.

(16) In a reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel 13.15 g. of copolymer comprising 95 mole percent of acrylic acid and 5 mole percent of B-chloroethyl acrylate are dissolved in 100 ml. of dimethylformamide.

A mixture of 14.8 ml. of 40% aqueous solution of trimethylamine and 15 ml. of dimethylformamide is added dropwise at room temperature to this solution. The solution is heated to 35 C. By adding ml. of Water to the turbid solution it becomes clear. After 10 minutes another 10 ml. of water are added. Subsequently the reaction temperature is maintained at 35 C. to 2 hours.

The copolymer is isolated by pouring in acetone. The total bulk is then dissolved again in water and the pH of the resulting solution is brought at 7 by the addition of sodium hydroxide.

Yield: 12.2 g. of copolymer with the same recurring units as in preparation 14, but in a proportion of -1, 4 and 95 mole percent respectively.

(17) In a reaction vessel fitted with a stirrer, a reflux condenser and a dropping funnel 12.82 g. of copolymer comprising 13.6 mole percent of acrylic acid and 86.4 mole percent of B-chloroethyl acrylate are dissolved in acetone to a total volume of 50 ml. Then 50 ml. of 11.8% aqueous solution of trimethylamine are added dropwise at room temperature to this solution. The quaternization is slightly exothermic and the temperature rises to 28 C.

The mixture is then heated to 40 C. for 1 hour and subsequently at reflux temperature for 1 hour, The copolymer is isolated by the addition of a little amount of hydrochloric acid, washed with water till free of hydrochloric acid, and dissolved in water by the addition of trimethylamine.

Yield: 9.7 g. of copolymer with the same recurring units as in preparation 14, but in a proportion of 7, 79, and 14 mole percent respectively. The acrylic acid units are present in the form of their trimethylammonium salt.

(18) Copolymer of N-methacryloyloxyethyl-trimethylammonium methyl sulphate, sodium acrylate, and pchloroethyl acrylate In a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, 245 ml. of 31.1% aqueous solution of N methacryloyl oxyethyl N,N diethyl-N- methyl ammonium methylsulphate and 4.76 g. of acrylic acid are mixed and diluted with water to a total volume of 400 ml.

0.5 g. of potassium persulphate and 0.5 g. of potassium metabisulphite are added to the solution, and nitrogen is led through it. The mixture is heated to 30 C.

(14) 29 g. of B-chloroethyl acrylate diluted with 30 ml. of dimethylformamide are then added dropwise in approximately 45 min.

After a reaction period of 4 hours at 30 C. a viscous white solution is obtained, which is diluted with water to 900 ml. after the addition of sodium hydroxide to adjust the pH to 7.

Yield: 95 g. of copolymer with the following recurring units in a proportion of 58.9, 25.4, and 15.7 mole percent respectively.

-- and CHr-CH (19) Copolymer of N-methacryloyloxyethyl-N-diethylammonium chloride, fl-chloroethyl acrylate, and sodium acrylate 70 g. of diethylaminoethyl methacrylate are brought in a reaction vessel of 500 ml. fitted with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet. Then 31.6 ml. of concentrated hydrochloric acid are added thereto dropwise whilst cooling with ice-water. The pH of the solution is 6. Then g. of acrylic acid are added, whereupon the total volume is adjusted to 150 ml. by the addition of water. Thereupon 15 g. of fi-chloroethyl acrylate filled up with dimethylformamide to 50 ml, are added. Finally 0.5 g. of potassium persulphate and 0.5 g. of sodium metabisulphite are added. A nitrogen current is conducted through the clear solution, while it is heated to 50 C. with stirring. After 45 minutes a very viscous turbid solution is obtained, to which 50 ml. of water are added. After 4 h. the pH of the viscous solution is ad- 35 justed to 7 by means of sodium hydroxide. Finally, the solution is diluted with water to 1141 ml. of volume.

The solution contained 130 g. of copolymer with the following recurring units:

CH3 CHz OHg-CH and CH2CH- 21:0 =0 L COONa 41112 41112 +112 Ck (EH2 +NH l C111 C2H Proportion of the recurring units: 54.1, 15.9, and 30 mole percent respectively.

(20) Copolymer of sodium acrylate and p-chloroethyl acrylate In a reaction vessel fitted with a stirrer, a reflux condenser sealed with a calcium chloride tube, a nitrogen inlet, and a thermometer, 90 g. of acrylic acid, 10 g. of p-chloroethyl acrylate, and 500 mg. of azodiisobutyronitrile are dissolved at room temperature in 750 ml. of benzene, which is free from thiophene and Water. The

homogeneous solution is stirred and while a gentle nitrogen stream is bubbled through the reaction mass it is heated at reflux temperature. The polymerization is slightly exothermic and the clear solution gradually becomes turbid. The resulting copolymer of acrylic acid and ,B-chloroethyl acrylate deposits.

After 3% hours the copolymer has precipitated completely. The polymer suspension is filtered in benzene and after being washed with 0.4 l. of benzene, 100 g. of oopolymer are obtained in the form of a white powder. The

copolymer is composed of randomly distributed units according to the following formulae:

CH2 CH2 $1 and contains 94.4 mole percent of acrylic acid. By dissolving in water and neutralizing with sodium hydroxide the acrylic acid groups are converted into sodium acrylate groups.

(21) The process of preparation is repeated with the following reagents:

80 g. of acrylic acid 20 g. of p-chloroethyl acrylate 500 mg. of azodiisobutyronitrile Yield: 98.5 g. of copolymer of acrylic acid and ,G-chloroethyl acrylate. The copolymer contains 88 mole percent of acrylic acid. By dissolution in water and neutralization with sodium hydroxide the copolymer of sodium acrylate and fl-chloroethyl acrylate is formed.

CHz-CH (22) Copolymer of styrene sulphonic acid, acrylic acid, and fi-chloroethyl acrylate in trimethylammonium salt form (A) Copolymer of styrene, acrylic acid, and fJ-chloroethyl acrylate.-In a reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a nitrogen inlet, and a thermometer, 2.78 g. of 90% aqueous solution of dodecylated oxydibenzene disodium sulphonate, 8.94 g. of 28% aqueous solution of the sodium salt of tetradecyl sulphate, and 1 g. of ammonium persulphate are dis solved in 250 ml. of demineralised water.

Whilst stirring and conducting a gentle nitrogen current through the mass, the latter is heated to 70 C. A homogeneous mixture of 10.8 g. of acrylic acid, 6.725 g. of fi-chloroethyl acrylate, and 83.2 g. of styrene is added dropwise and gradually in 30 minutes, while the temperature is maintained at 70 C.

After a total reaction time of 3 /2 hours and after addition of a little acetone, a homogeneous latex is obtained, from which the copolymer of styrene, acrylic acid, and B-chloroethyl acrylate is isolated. The powdery precipitate is brought in 600 ml. of methanol, washed with 400 ml. of methanol, sucked off, and dried in vacuo at room temperature. The copolymer comprises 10.4 mole percent of acrylic acid, 5.5 mole percent of fi-chloroethyl acrylate; and 84 mole percent of styrene.

(B) Sulphonation.-In a reaction vessel fitted with a stirrer, a thermometer, a reflux condenser sealed with a calcium chloride tube, and a dropping funnel, a 1:1 molar complex of sulphur trioxide and dioxan is formed previously in dichloroethane. Therefore, 100 ml. of anhydrous dicholoroethane and 24.6 g. of anhydrous dioxan are brought in the reaction vessel. Whilst cooling, a mixture of 24 g. of freshly distilled sulphur trioxide and 50ml. of dichloroethane is added dropwise at such a rate that the temperature of the reaction medium is maintained at approximatively 25 C.

A solution of 37.6 g. of the copolymer formed as described under (A) in 400 ml. of anhydrous dichloroethane is added quickly at 4050 C. to the sulphur trioxide/dioxan complex formed. There is no perceptible exothermic reaction.

Initially a homogeneous solution is obtained, from which after a reaction period of 1 h. at 25 C. a jellylike mass is formed. After keeping overnight at room temperature 250 ml. of n-hexane are added to the mass. Whilst thoroughly stirring, the sulphonated product is isolated in the form of small polymer pieces. The supernatant liquid is decanted and after being washed again with a mixture of 500 ml. of dichloroethane and 200 ml. of n-hexane, the copolymer dissolves in water. The pH of the solution is adjusted to 6 by means of trimethylamine. The aqueous solution is then concentrated by evaporation till it obtains a bright aspect. After filtration, 500 ml. of a solution at pH 5.8 comprising 63.9 g. of copolymer comprising the following randomly distributed units are obtained:

Proportion of the recurring units: 63, 13.5, and 2.5 mole percent. The remaining 21 mole percent are nonmodified styrene units.

(23) Copolymer of the sodium salt of 'y-sulphopropyl acrylate, sodium acrylate, and fi-chloroethyl acrylate.- In a reaction vessel equipped with a stirrer and a dropping funnel 7.2 g. of copolymer of acrylic acid and B- chloroethyl acrylate prepared according to preparation 20 and comprising 94.4 mole percent of acrylic acid, are dissolved in ml. of water. The pH of the resulting solution is adjusted to 7 at room temperature by means of 5 N sodium hydroxide. The mixture is then heated together with 12.2 g. of propane-sultone on an oil-bath at 80 C. During the reaction the pH is maintained at 7 by means of 5 N sodium hydroxide.

After a reaction period of 1 h. the cooled solution is poured in 1 l. of methanol whilst stirring, and after filtration washed again with 200 ml. of methanol. The sulphonated polymer is then dissolved in water.

Yield: ml. of solution comprising 8.7 g. of copolymer with the following recurring units:

Proportion of the recurring units: 54, 7.5, and 38.5 mole percent respectively.

(24) The process of preparation 23 is repeated with the following ingredients:

45 g. of copolymer of acrylic acid and B-chloroethyl acrylate of preparation 21 (80 mole percent of acrylic acid) 600 ml. of water 61 g. of propane-sultone Yield: 650 ml. of solution comprising 62.4 g. of copolymer with the following proportion of recurring units: 53.5, 7.2, and 39.3 mole percent respectively.

(25) Copolymer of styrene, the sodium salt of 'y-sulphopropyl acrylate, sodium acrylate, and ,B-chloroethyl acrylate (A) Copolymer of styrene, sodium acrylate, and chloroethyl acrylate.In a reaction vessel equipped with a reflux condenser, a nitrogen inlet, and a stirrer, 35.5 g. of B-chloroethyl acrylate, 25.1 g. of styrene, and 42.4 g. of acrylic acid are dissolved in 200 ml. of acetone.

5 g. of azo-bis-isobutylronitrile are added to this solution, which is then heated at reflux temperature while it is stirred and while a gentle nitrogen current is led through it. The polymerization is not exothermic and the initial temperature of 66 C. gradually decreases to 56 C.. which is the boiling point of pure acetone. After a polymerization time of 24 hours the viscous solution is poured in 3 l. of distilled water whilst stirring. A fibrous polymer is obtained, which upon washing with water is dissolved in a minimum amount of acetone. The pH of the resulting solution is adjusted to 7 with 1 N sodium hydroxide. Subsequently the solution is partially concentrated by evaporation in vacuo to remove the acetone. One litre of solution is obtained containing 9.5% of copolymer comprising 22.5 mole percent of styrene, 55 mole percent of sodium acrylate, and 22.5 mole percent of fl-chloroethyl acrylate.

(B) Reaction with l,3-propanesultone.In a reaction vessel equipped with a stirrer, a reflux condenser, and a dropping funnel, 47.4 g. of the copolymer formed as described under (A) are dissolved in water till a total volume of 498 ml. This solution is neutralized with N sodium hydroxide till pH 7 and then heated to 70 C. Then 30.5 g. of 1,3-propanesultone are added dropwise while the temperature is maintained at 70 C. and the pH at 7 by addition of 2 N sodium hydroxide. The dropwise addition is regulated so that the whole amount is added within 45 minutes. Subsequently the mixture is stirred for 15 minutes at 70 C., whereupon the homogeneous solution is poured in a mixture of 500 ml. of acetone and 500 ml. of methanol. The sticky residue is washed twice with a mixture of 200 ml. of acetone and 200 ml. of methanol and then dissolved in water.

Yield: 57.2 g. of copolymer comprising the following recurring units:

The proportion of recurring units in the copolymer is as follows: 22.5, 26.2, 40.1, 11.2 mole percent respectively.

The sodium acrylate units resulted from the partial saponification of B-chloroethyl acrylate units.

(26) Copolymer of styrene, the sodium salt of 'y-sulphopropyl methacrylate, sodium methacrylate, B-chloroethyl acrylate, and sodium acrylate (A) Copolymer of styrene, methacrylic acid, and 18- chloroethyl acrylate.In a reaction vessel fitted with a reflux condenser, a nitrogen inlet, and a stirrer, 21.4 g. of styrene, 57.8 g. of methacrylic acid, and 20.8 g. of B- chloroethyl acrylate are dissolved in 200 ml. of acetone.

To the solution 2.5 g. of azo-bis-isobutyronitrile are added. Whilst stirring and conducting a gentle nitrogen current through the solution, the latter is heated at reflux temperature. Initially only a small amount of precipitate is formed, which by the addition of 25 ml. of methanol dissolves again. After a reflux time of 15 hours a viscous solution is obtained, which after dilution with 250 ml. of methanol is poured in 5 l. of distilled water. A fibrous copolymer is obtained, which after washing with water is dissolved in 500 ml. of acetone. The pH of the solution is adjusted at 7 by means of 1 N sodium hydroxide. The solution is then inspissated partially to remove the acetone. An amount of 930 ml. of solution is obtained comprising 99 g. of copolymer. The copolymer contains 20 mole percent of styrene, 65 mole persent of sodium methacrylate, and 15 mole percent of B-chloroethyl acrylate. The intrinsic viscosity of the copolymer is 0.35 dl./g. in methanol at 25 C.

(B) Reaction with 1,3-propane-sultone.In a reaction vessel fitted with a stirrer, a reflux condenser, and a dropping funnel, 46.2 g. of the copolymer prepared as described under (A) are dissolved in water to a total volume of 434 ml. The resulting solution is neutralized by means of 5 N sodium hydroxide and heated to 70 C. Whilst stirring 36.6 g. of 1,3-propanesultone are added at this temperature in 1 hour, while the pH is maintained at 7 by the addition of 2 N sodium hydroxide. The mixture is stirred for another 15 minutes at 70 C. A homogeneous solution is obtained, from which the copolymer is isolated by decanting in a mixture of equal volumes of methanol and acetone. The sticky residue is washed twice with a mixture of 200 ml. of acetone and 200 ml. of methanol and then dissolved in water.

Yield: 69.1 g. of copolymer with the following recurring L tmTl to CH2 (EH2 $1 The proportion of the recurring units is 20, 41, 24, 8 and 7 mole percent respectively, the sodium acrylate units being formed during the reaction by partial saponification of 3-chloroethyl acrylate.

(27) Copolymer of styrene, fi-chloroethyl acrylate, and the sodium salt of maleic acid In a reaction vessel fitted with a reflux condenser, a nitrogen inlet, and a stirrer, 45.7 g. of styrene, 6.5 of ,8- chloroethyl acrylate, and 47.8 g. of maleic anhydride are dissolved in 500 m1. of benzene. To this solution 0.5 g. of azo-bis-isobutyronitrile is added while nitrogen is bubbled through this solution, which is heated to 70 C. with stirring. The polymerisation is slightly exothermic and 15 minutes later the polymer starts precipitating. After 45 minutes stirring becomes more diflicult and 150 ml. of benzene are added. After a reaction time of 3% hours at 70 C. the precipitated copolymer is filtered with suction, washed with n-hexane, and dried in vacuo at room temperature.

Yield: g. of copolymer with the following recurring units:

H2 Na H2 in The proportion of the recurring units is 48.5, 3, and 48.5 mole percent respectively.

(28) The process of preparation 27 is repeated with the following reagents:

49.4 g. of styrene 46.55 g. of maleic anhydride 6.72 g. of fl-chloroethyl acrylate 500 m1. of toluene 0.5 g. of azo-bis-isobutyronitrile Yield: 100 g. of copolymer comprising recurring units in the following proportions: 47.5, 5.5, and 47.5 mole percent respectively.

In the first example hereinafter the surface resistivity of the different copolymers according to Preparations 1 to 28 is measured. In Examples 6 to 11 the application of electroconductive polymeric materials according to the invention is described as antistatic agents in normal photographic materials, whereas in Examples 2 to 5 their application in electrophotographic recording elements is described. In Example 12 the use of the electroconductive copolymers of the invention is described in the manufacture of a recording material in which information is stored in the form of electric charges on a dielectric surface. The storage surface consists of a mosaic of small squares of conductive material on the dielectric plate. This mosaic of conductive squares is manufactured by exposing a layer of conductive copolymer, mixed with a finely divided black pigment, through a dot-screen to short duration high-intensity flashes, e.g. of an electronic flash lamp, or by exposing the layer through the same screen at a temperature between 50 and 200 C. for longer periods of time. The exposed areas of the conductive copolymer layer become cross-linked and then insoluble in water or organic solvents, whereas the noncrosslin'ked areas can be washed away, leaving a mosaic of electroconductive squares on the dielectric surface. These squares can be image-wise charged electrically, e.g. by means of a charged needle, and the charges can be developed electrophoretically to a visible image.

In addition, the copolymers of the invention may also be used in other electrographic processes. A survey of these different processes has been given by C. J. Claus in Phot. Sci. Eng. 7 (1963) pages 5-13. The electroconductive polymers may be used in combination with coatings of various inorganic as well as organic photoconductive substances such as those described in the Belgian patent specification 587,300, filed February 1969 by Gevaert Photo-Producten N.V., the United Kingdom patent specifications 964,871, filed Feb. 26, 1959, 964,873 filed Mar. 30, 1960, 964,874 filed Mar. 30, 1960, 964,875 filed Apr. 21, 1960, 964,876 filed Apr. 21, 1960, 964,877 filed May 2, 1960, 964,879 filed Apr. 26, 1960, 970,937 filed Dec. 9, 1960, 980,879 filed Feb. 17, 1961 and 980,880 filed Feb. 17, 1961 all by Gevaert Photo-Producten N.V., in the German patent specification 1,058,- 836 of Kalle & C0. A6. filed Apr. 14, 1956 and in the Canadian patent specification 568,707 of Kalle & C0. A6. issued Jan. 6, 1959. These photoconductive substances may be combined with insulating binder agents, known i.a. from the United States patent specifications 2,197,- 552 of Joseph N. Kuzmick, issued Apr. 16, 1940, 2,297,- 691 of Chester F. Carlson issued Oct. 6, 1942, 2,485,589 of Frank Gray issued Oct. 25, 1949, 2,551,582 of Chester F. Carlson issued May 8, 1951, 2,599,542 of Chester F. Carlson issued June 10, 1952, the United Kingdom patent specifications 566,278 filed June 21, 1943 by Rothschild S. & Cathodeon Ltd., 693,112 filed May 9, 1950 by Battelle Development Corporation, 700,502 filed Apr. 26, 1949 by Office National dEtudes et de Recherches Aronautiques, the Belgian patent specification 612,102 filed Dec. 29, 1961 by Gevaert Photo-Producten N.V., the French patent specification 1,485,839 filed June 24, 1966 by Gevaert-Agfa N.V., Canadian patent specification 824,086 of Gevaert-Agfa N.V., issued Sept. 30, 1969, and the Belgian patent specifications 711,376 filed Feb. 28, 1968 and 714,257 filed Apr. 26, 1968 both by Gevaert- Agfa N.V.

Suitable dispersing agents for dispersing photoconductive materials in an aqueous medium are described in the French patent specification 1,540,020 filed Sept. 4, 1967 by Gevaert-Agfa N.V. and as is generally known the photoconductive substances can be spectrally sensitized, e.g. as described in the French patent specifications 1,547,- 196 filed Dec. 14, 1967 and 1,560,976 filed Apr. 24, 1968 both by Gevaert-Agfa N.V.

The following examples illustrate the present invention.

EXAMPLE 1 An aqueous solution of the copolymers described in the preceding preparations was coated on a glassine paper of '60 g. per sq. m. in such a Way that 2 g. of solids were present per sq. m. The coated layer was dried first at 30 to 40 C. and subsequently dried thoroughly at 100 C. The total drying time may be varied between two and fifteen minutes, without impairing the photographic results.

Table I shows the results obtained upon measurement of the surface resistivity of these layers. At the same time the degree of solubility in water after drying is given.

This table proves that within the scope of this invention electroconductive transparent copolymer layers insoluble in water can be obtained.

TABLE I Surface resistivity in 10 ohm] cm. at- Solubility in water at 20 C. after drying 15% RH RH RH Eleetroconductlve copolymer of Preparation number:

14. 2 1. 47 266 42. 5 3. 54 0. 16 2. 83 0. 68 133 2. 83 213 7. 1 1. 15 0. 26 2. 24 2. 03 1. 22 0. 47 1. 01 0. 427 16. 4 1. 58 6. 3 1. 01 8. 9 0. 84 85 5. 8 49 0. 71 510 20. 3 9, 300 133 38. 6 7. 6 630 15. 2 5. 3 0. 25 swollen.

21 In the copolymers wherein the proportion of the units that are reactive with halogen atoms is exceeding the amount needed to cross-link and thus to insolubilize the copolymer upon heating, in general the excess of these units serves to enhance the conductivity or the solubility in water before heating of the copolymer.

EXAMPLE 2 A glassine paper weighing 60 g. per sq. m. was coated as described in Example 1 with an aqueous solution of the copolymer of N-acryloyloxyethylpyridinium chloride, fl-chloroethyl acrylate, and sodium acrylate of preparation 1 in a ratio of 2 g. of solid copolymer per sq. m., and dried as specified in Example 1.

An amount of 20 g. of photoconductive zinc oxide, 25 ml. of water, and 1 ml. of a solution of a copolymer of maleic anhydride and N-vinylpyrrolidone (51.7:48.3) in a concentrated technical grade ammonium hydroxide solution were mixed for 10 minutes with a high speed stirrer, e.g. a Kothofi mixer. The dispersion was then added to a solution of 2.5 g. of the copolymer of vinyl acetate and crotonic acid (94.4/5.6) in 25 ml. of water and 0.2 ml. of 25% by Weight aqueous ammonia solution. The composition was sensitized with Direct Green 59 (Colour Index 34,040) on the form of a 0.5 solution in water. An amount of 1.5 ml. of this sensitizer solution was added together with 1.75 ml. of Mordant Red 5 (Colour Index 14,290) in the form of a 0.5% solution in water.

The photoconductive dispersion essentially consisting of zinc oxide as described above was coated on the previously coated and dried layer consisting of the above copolymer of N-acryloyloxyethylpyridinium chloride, e-chloroethyl acrylate, and sodium acrylate. The zinc oxide layer was dried for minutes at 100 C.

The dried photoconductive material as prepared above produced sharp and contrasting images after storage in the dark for some hours, image-wise exposure and development according to standard electrophotographic techniques. The quality of the images obtained was not only determined by the inherent properties of the photoconductive zinc oxide layer, for which we refer to the French patent specification 1,547,196 filed Dec. 12, 1967 by Gevaert-Agfa N.V., but also by the highly electroconductive copolymer layer.

EXAMPLE 3 The process of Example 2 was repeated with the proviso, however, that the conductive copolymer used in the first coating was replaced by the copolymer of 1,2-dimethyl-5-vinylpyridinium methylsulphate, B-chloroethyl acrylate, and sodium acrylate of Preparation 5.

The dried photoconductive material, when stored in the dark for some hours, produced sharp and contrasting images upon image-wise exposure and development as indicated in Example 2.

EXAMPLE 4 Equally good results were obtained when replacing the copolymer for the preparation of the conductive layer in Example 2 by the copolymer of the sodium salt of 7-801- phopropyl acrylate, sodium acrylate, and p-chloroethyl acrylate of preparation 23.

A photoconductive zinc oxide dispersion having the following composition was coated on this conductive paper base:

2.866 kg. of 1,2-dichloroethane,

0.615 kg. of 40% solution of copolymer of vinyl acetate and vinyl laurate (80:20 mole percent) in 1,2-dichloroethane,

0.375 kg. of solution of copolymer of vinyl chloride, vinyl acetate, and vinyl alcohol (91 :3 :6 mole percent) in 1,2-dichloroethane,

0.180 kg. of 20% solution of copolymer of vinyl chloride,

22 vinyl acetate, and maleic anhydride (:8:2 mole percent) in 1,2-dichloroethane, and 1 kg. of zinc oxide (prepared according to the French process).

This composition was treated once in a homogenizer at 250 kg./ sq. cm. A composition comprising the following ingredients was then added thereto:

34 ml. of 10% solution of tetrachlorophthalic anhydride in ethanol, 12 ml. of 10% solution of acid butyl phosphate in ethanol, 13 ml. of 0.5% solution in diacetone alcohol of the dye according to the following structural formula:

0 O \CCH=CH-CH=C/ (LH2)is0.-NH-c o-CH;

(CHg) SOzNH--C O-CHa 44 ml. of 1% solution of bromophenol blue in methanol,

and

8 ml. of 1% solution in 1,2-dichloroethane of a compound corresponding to the following structural formula:

0 @Wo 0 N11--Br This composition was coated in a ratio of 20 g. of zinc oxide per sq. m. on a paper web coated as in Example 2 with an electro-conductive layer, with the proviso, however, that the copolymer therein has been replaced by the copolymer of the sodium salt of 'y-sulphopropyl acrylate, sodium acrylate, and B-chloroethyl acrylate of preparation 23.

The resulting layer was dried and upon dark adaptation fed into a common development apparatus for electrophotographic material. A sharp image, which entirely met the presently set commercial standards, was obtained.

EXAMPLE 5 The good properties of the conductive polymers as described in this invention also mainfested themselves when an organic semiconductor was coated on such conductive base paper as described in Example 3.

The organic semiconductor layer was coated from the following composition:

566 ml. of a 20% solution of poly-1,2-dihydro-2,2,4-trimethylquinoline in methylene chloride 266 ml. of a silicone resin in toluene, and

858 ml. of methylene chloride.

This composition was coated on the electroconductive paper web, so that upon drying 2.5 g. of solid matter were present per sq. m.

After dark adaptation the layer was charged by means of a negative corona discharge, exposed to an incandescent bulb through a 0.3 wedge, and developed electrophoretically. An image of the wedge was obtained with a maximum density that was typical for highly conductive supports.

23 EXAMPLE 6 A cellulose triacetate support comprising 15% by weight of triphenyl phosphate was coated with an antistatic layer from the following solutions:

105 ml. of 9.5% by weight aqueous solution of a copolymer of vinylbenzyltrimethylammonium chloride, vinylbenzyl chloride, and acrylic acid (46:49.8:4.2 mole percent) (see preparation 12) (the pH value of this solution had been adjusted to 7.0 by addition of sodium hyhydroxide),

395 ml. of methanol, and

500 ml. of acetone.

The thickness of the resulting layers was 0.15 g./sq. m. After drying for 5 minutes at 100 C. a clear layer was obtained, which adhered excellently to the cellulose triacetate film support.

The surface resistivity of the resulting material was then measured and compared with that of a same cellulose triacetate film, which, however, had not been provided with an antistatic layer.

Surface resistivity in 10 ohm/l sq. cm. at

30% 60% relative relative humidity humidity Before processing 0. 0068 0. 000 After processing 120 0. 09

The comparison material had a surface resistivity of more than 500 10 ohm/10 sq. cm. in both cases.

The processing was carried out in common photographic baths, viz. 5 minutes in an alkaline developing bath, whereupon the materials were rinsed with pure water, and minutes in an acid fixing bath, whereupon the material was rinsed for 1 hour with running water.

EXAMPLE 7 A cellulose triacetate support containing by weight of triphenyl phosphate was coated with an antistatic layer from the following solution at a ratio of 0.12 g. of polymer/sq. m.:

100 ml. of 10.2% by weight aqueous solution of a copolymer of N methacryloyloxyethyl trimethylammonium methylsulphate, acrylic acid, and S-chloroethyl acrylate (58.9:25.4: 15.7 mole percent) (see preparation 18). The pH-value of this solution had been adjusted to 7.0 by addition of sodium hydroxide;

400 ml. of methanol, and

500 ml. of acetone.

After drying for 5 minutes at 100 C. the surface resistivity of the resulting material was measured and compared with that of a same cellulose triacetate film which,

however, had not been provided with an antistatic layer.

Surface resistivity in 10 ohm/10 sq. cm. at-

30% 60% relative relative humidity humidity Before processing 15 0. 06 After processing 50 0.22

The comparison material had a surface resistivity above 500x 10 ohm/ 10 sq. cm. The same photographic processing baths were used as in Example 6.

EXAMPLE 8 A biaxially oriented polyethylene terephthalate support was coated with an antistatic layer from the following composition at a ratio of 0.18 g. of polymer/sq. m.:

61 ml. of 16.4% by weight aqueous solution of a copolymer of N-acryioyloxyethyl-trimethylammonium chloride, acrylic acid, and fi-chlorethyl acrylate (7:79:14 mole percent) (see preparation 17). The pH-value of this solution had been adjusted to 7.0 by addition of sodium hydroxide,

39 ml. of water,

400 ml. of methanol, and

500 ml. of acetone.

The coated support was then dried for 5 minutes at 105 C., so that a clear layer was obtained, which adhered very well to the polyester support.

Subsequently the surface resistivity of the resulting material was measured before and after processing in photographic baths as indicated in Example 6 at 30% and 60% relative humidity.

Surface resistivity in 10 ohm/10 sq. cm. at

30% 60% relative relative humidity humidity Before processing 0. 036 0. 0008 After processing 2. 5 0. 12

A same polyethylene terephthalate support, which, however, had not been provided with an antistatic layer, had a surface resistivity above 500 10 ohm/ 10 sq. cm.

EXAMPLE 9 Surface resistivity in 10 ohm/l0 sq. cm. at-

307 607 relativ relativg humidity humidity Before processing 0. 34 0. 0075 After processing 2 0.015

EXAMPLE 10 A non-stretched polyethylene terephthalate support was covered according to known methods with a subbing layer of a copolymer of vinyl chloride, vinylidene chloride, butyl acrylate, and itaconic acid (63:3025 :2 mole percent, whereupon the polyethylene terephthalate fihn was oriented. Subsequently, an antistatic layer was applied thereto from the following solution at a ratio of 0.25 g./ sq. m.:

ml. of 12.7% by weight aqueous solution of a copolymer of styrene, styrene sulphonic acid, acrylic acid, and B-chloroethyl acrylate (21:63:13.5:2.5 mole percent (see preparation 22). The pH of this solution was adjusted to 5.8 by addition of trimethylamine,

20 ml. of water,

400 ml. of methanol, and

500 ml. of acetone.

After drying for 5 min. at C. a clear layer was obtained, which adhered very well to the subbed polyethylene terephthalate film.

The surface resistivity of the resulting material was measured at different relative humidities before and after photographic processing as indicated in Example 6.

Surface resistivity in 10 ohm/l sq. cm. at

EXAMPLE 11 A 10% by weight aqueous solution of the copolymer of styrene, maleic anhydride, and fl-chloroethyl acrylate (47.5 :547.5 mole percent as prepared in preparation 28 was formed. The pH-value of this solution was adjusted to 7.0 by addition of sodium hydroxide.

To 100 ml. of this solution 400 ml. of methanol and 500 ml. of acetone were added. This solution was applied according to usual methods to a cellulose triacetate film having a thickness of 140 1. The resulting material was dried for 3 minutes at 100 C.

Subsequently a gelatin subbing layer was applied thereto from a gelatin dispersion having the following composition:

Gelatin g 1 Water ml 20 Concentrated ammonium hydroxide ml 0.05 Ethanol ml 25 Acetone ml 55 Surface resistivity in 10 ohm/10 sq. cm. at

30% 60% relative relative humidity humidity Comparison material l0 0. 1 Test material 7 0. 1

EXAMPLE 12 To a conductive support, e.g. an aluminum foil or an electroconductive paper, a layer of polystyrene or of an alkyd resin of thickness was applied. Onto this layer was coated a aqueous solution of copolymer of vinylbenzyltrimethylammonium chloride, vinylbenzyl chloride and sodium acrylate. This copolymer has been prepared according to the method of preparation 9 and thus contains 30, 61.2 and 8.8 mole percent respectively of the monomers mentioned. Of the solution formed 20 ml. were mixed with 30 ml. of water, 1 g. of carbon black, 1 ml. of saponine solution, and 5 ml. of ethanol. This mixture was applied to the insulating layer of polystyrene or alkyd resin in such a way that after drying a layer of some 5 1 was left.

By means of about three flashes of 8 millisec. provided by a flash lamp of 1.03 watt sec./sq. cm. through a dot screen the layer was heated locally. On the exposed areas the copolymer had been crosslinked, whereas at the non-exposed areas the covering layer was Washed away by brushing and simultaneous spraying with water. Each dot of the screen together with the insulating layer and the conductive support formed a condensor, which by 26 contact with a needle to which a tension had been applied, could be charged. Tensions of 200 v. were sufiicient to apply a charge to the conductive dots, which in an electrophoretic development could be made visible.

We claim:

1. Sheet material coated on at least one side with an electroconductive layer having a surface resistivity measured at 15% RH lower than 10 ohm/sq. cm., said electroconductive layer consisting essentially of a random addition copolymer comprising:

(A) 20 to 95 mole percent of monomeric units of at least one electroconductive cationic or anionic, 0:, 3- ethylenically unsaturated monomer,

(B) 5 to mole percent of monomeric units of at least one u,/3-ethylenically unsaturated monomer carrying a reactive halogen atom,

(C) 0 to 44 mole percent of monomeric units of at least one a,;8-ethylenically unsaturated monomer carrying an acidic group in free acid or salt form which is reactive with the reactive halogen atoms of units (B), at least about 5 mole percent of said units (C) being present where said units (A) are unreactive with the reactive halogen atoms of units said copolymer being initially water-soluble and converted by heating to 30-l80 C. to water-insoluble form by an internal cross-linking reaction between said reactive halogen atoms and at least one of the units (A) and units (C).

2. Sheet material according to claim 1, wherein the copolymer is a copolymer of N-acryloyl-oxyethyl-N-trimethylammonium methylsulphate, sodium acrylate, and fi-cholorethyl acrylate.

3. Sheet material according to claim 1, wherein the copolymer is a copolymer of N-methacryloyloxyethyl-N- diethylammonium chloride, sodium acrylate, and ,B-chloroethyl acrylate.

4. Sheet material according to claim 1, wherein the copolymer is a copolymer of N-acryloyloxyethyl-N-trimethylammonium chloride, sodium acrylate, and p-chloroethyl acrylate.

5. Sheet material according to claim 1, wherein the copolymer is a copolymer of sodium acrylate and S-choloethyl acrylate.

6. Sheet material according to claim 1, wherein a photoconductive layer is applied to the electroconductive layer to form an electrophotographic recording element.

7. Sheet material according to claim 1, wherein an insulating layer is applied to the electroconductive layer to form an electrographic recording element.

8. Sheet material according to claim 1, wherein a gelatin subbing layer is applied to the electroconductive layer followed by a light-sensitive gelatin silver halide emulsion layer to form a photographic recording element.

References Cited UNITED STATES PATENTS 3,515,707 6/1970 Reimschnessel 162138 X 3,329,560 7/1967 Von Schlickh et al. 162-138 X 3,293,115 12/1966 Lucken 162-138 X 3,248,279 4/ 1966 Geyer 162138 3,011,918 12/1961 Silvernail et a1. 11735.6 X

GEORGE F. LESMES, Primary Examiner J. R. MILLER, Assistant Examiner US. Cl. X.R.

96-15; 117-201, 218, 219; 162138; 260-795 NV, 80.73, 80.8, 86.1 E 

